1. Field of the Invention
The invention relates to digital information distribution systems and, more particularly, the invention relates to an asynchronous serial interface (ASI) ring network for routing digital information to multiple users.
2. Description of the Background Art
Digital video can be distributed through networks that utilize asynchronous transfer mode (ATM) and packet over SONET. However, both of these types of digital video distribution systems are not cost effective and require significant overhead bandwidth for each respective packet format plus configuration and control overhead to facilitate network routing. A more efficient network solution for point-to-point transmission and delivery of Moving Pictures Experts Group (MPEG) packets is known as DVB-ASI (Digital Video Broadcast/Asynchronous Serial Interface). DVB-ASI is described in European Standard EN 50083 entitled “Cable Distribution System for Television, Sound, and Interactive Multimedia Signals”, March 1997. This specification defines a protocol for distributing digital video in the form of MPEG packets at a rate of 270 Mbps. The actual data carriage under this protocol is 216 Mbps. Although the DVB-ASI protocol is well suited for simplex, point-to-point communications, a system based on this protocol is not capable of supporting high speed data transmissions that are necessary for multi-user digital video distribution systems. Furthermore, because of the limited data carrying capability, the DVB-ASI protocol does not efficiently utilize the bandwidth that is available for optical fiber based systems, i.e., a bandwidth that exceed 1 Gbps.
Therefore, there is a need in the art for a multi-user, digital video distribution system that provides high speed transmissions, e.g., more than a gigabit per second, in conjunction with a low overhead transmission protocol.